The Hog Island Chain, which starts south of "C18" canal spur and ends north of the "M" canal, are a geologic formation known as a Plestocene Sand Ridge. The sand ridge can actually be seen from the "satelite" topo map with great clarity and"Grassy Waters" sits on top of this sand ridge.
The Pleistocene Epoch (1.8 million to 10,000 years ago) also known as the "ice age", was actually made up of both cold glacial periods and warm interglacial periods. During the glacial periods, sea water flowed into expanding ice sheets, decreasing the sea level. At peak glacial times, the sea level dropped several times it's present size. During interglacial periods, the climate increased in temperture, causing the melting of the ice sheets and increasing the sea level several feet above the present day sea level.
During the last Pleistocene interglacial period, 120,000 years ago, the "Hog Island Chain" was a coastal sand dune caused by wave action depositing sand onto the shoreline. This sand dune continues to be higher in elevation then the surrounding wetland, which is today the Cities drinking water source. This drier tropical type upland is what "Hog Hammock trail" sits on.
To receive credit, you will have to visit the site at the coordinates and message me with the answers to the following questions before logging as a find:
1-At peak glacial stages, the sea level was how many feet below it's present level?
2-During these peak glacial stages, Florida was up to how many times it's current size?
3-At peak interglacial stages, the sea level was how many feet above present day levels?
4-From observing the area, how do you think the chain of islands has changed?